Xie Feng, Li Guanghuan, Yan Feng, Xiao Chengbin, Wang Pengju, Shen Xuehua, Yang Biao, Lin Han, Luo Huarong, Zhang Zuotai
School of Environmental Science and Engineering, Shenzhen Key Laboratory of Municipal Solid Waste Recycling Technology and Management, Southern University of Science and Technology, Shenzhen 518055, China.
Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, Southern University of Science and Technology, Shenzhen 518055, China.
Environ Sci Technol. 2025 Mar 4;59(8):3925-3936. doi: 10.1021/acs.est.4c09928. Epub 2025 Jan 28.
Solid-liquid biphasic absorbents are a promising solution for overcoming the high-energy consumption challenge faced by liquid amine-based CO capture technologies. However, their practical applications are often hindered by difficulties in separating viscous solid-phase products. This study introduces a novel nonaqueous absorbent system (PD/PZ/NMP) composed of 4-amino-1-methylpiperidine (PD), piperazine (PZ), and -methyl-2-pyrrolidone (NMP), engineered to produce easily separable powdery products. The PD/PZ/NMP absorbent achieves a CO loading of 0.86 mol-CO/mol-amine, with 91% of CO concentrated in the solid phase. It demonstrates excellent cyclic stability, maintaining a regeneration efficiency of 91% after five regeneration cycles, and reduces energy consumption by 52% compared with the conventional monoethanolamine absorbent. Remarkably, PZ plays a crucial role in regulating the crystal composition of solid-phase products, transforming them from a viscous state to a crystalline powder. Characterization and density functional theory analysis explain the crystal-phase regulation mechanism: PD absorbs CO to form zwitterions (PDHCOO), affording viscous products, and PZ forms protonated amines (PZH) and monocarbamates (PZCOO), which interact with PDHCOO via hydrogen bonding to form a crystalline powder. These findings demonstrate the CO capture efficacy of the PD/PZ/NMP absorbent and provide a robust theoretical framework for fabricating solid-liquid biphasic absorbents tailored for practical applications.
固液双相吸收剂是克服基于液态胺的二氧化碳捕集技术所面临的高能耗挑战的一种很有前景的解决方案。然而，它们的实际应用常常受到粘性固相产物分离困难的阻碍。本研究引入了一种新型非水吸收剂体系（PD/PZ/NMP），该体系由4-氨基-1-甲基哌啶（PD）、哌嗪（PZ）和N-甲基-2-吡咯烷酮（NMP）组成，设计用于生产易于分离的粉末状产物。PD/PZ/NMP吸收剂实现了0.86 mol CO/mol胺的二氧化碳负载量，其中91%的二氧化碳浓缩在固相中。它表现出优异的循环稳定性，在五个再生循环后保持91%的再生效率，与传统的单乙醇胺吸收剂相比，能耗降低了52%。值得注意的是，PZ在调节固相产物的晶体组成方面起着关键作用，将它们从粘性状态转变为结晶粉末。表征和密度泛函理论分析解释了晶相调节机制：PD吸收CO形成两性离子（PDHCOO），产生粘性产物，而PZ形成质子化胺（PZH）和单氨基甲酸盐（PZCOO），它们通过氢键与PDHCOO相互作用形成结晶粉末。这些发现证明了PD/PZ/NMP吸收剂的二氧化碳捕集效果，并为制造适用于实际应用的固液双相吸收剂提供了一个坚实的理论框架。
